It all started with a 7.8 magnitude earthquake that released a massive rock slide which could be heard by people 50 miles from the event’s epicenter. Ultimately, 90 million tons of rock would slip from the face of an Alaskan mountain and into the water just below the Lituya Glacier.

“People shake their heads when I tell them what I saw that night. I can’t help it if they don’t believe me. I know the glacier is hidden by the point when you’re in Anchorage Cove, but I know what I saw that night too. The glacier had risen in the air and moved forward so it was in sight. It must have risen several hundred feet. I don’t mean it was just hanging in the air. It seems to be solid, but it was jumping and shaking like crazy.” – Eyewitness account

And like the famous Isaac Newton stated in his third law, “for every action there is an equal and opposite reaction.” With that much rock falling into the water (*and a second slide involving sediment trapped in the Lituya Glacier), the water reacted in a way most people would think impossible.

Wave damage on the south shore of Lituya Bay, from Harbor Point to the spur southwest of Crillon Inlet | Photo: United States Geological Survey

All the displaced water resulted in what scientists now refer to as ‘mega tsunami’ measuring just short of 100′. Just a minute later, the wave slammed into the opposite landmass, climbing 1,720 vertical feet and decimating all the vegetation in its path. Bill and Vivian Swanson were anchored in Latuya bay when the earthquake struck and the tsunami was let loose. Their eyewitness account is simply staggering.

Eyewitness Account:

With the first jolt, I tumbled out of the bunk and looked toward the head of the bay where all the noise was coming from. The mountains were shaking something awful, with slide of rock and snow, but what I noticed mostly was the glacier, the north glacier, the one they call Lituya Glacier. I know you can’t ordinarily see that glacier from where I was anchored. People shake their heads when I tell them I saw it that night. I can’t help it if they don’t believe me. I know the glacier is hidden by the point when you’re in Anchorage Cove, but I know what I saw that night, too. The glacier had risen in the air and moved forward so it was in sight. It must have risen several hundred feet. I don’t mean it was just hanging in the air. It seems to be solid, but it was jumping and shaking like crazy. Big chunks of ice were falling off the face of it and down into the water. That was six miles away and they still looked like big chunks. They came off the glacier like a big load of rocks spilling out of a dump truck. That went on for a little while—its hard to tell just how long—and then suddenly the glacier dropped back out of sight and there was a big wall of water going over the point. The wave started for us right after that and I was too busy to tell what else was happening up there. – Bill Swanson (*Quote courtesy of Mader, C.L.; Gittings, M.L. (2002). “Modeling the 1958 Lituya Bay mega-tsunami, II” (PDF). The International Journal of the Tsunami Society. Tsunami Society. 20 (5): 241–245.